Wood Density Research Articles (Page 1)

ABSTRACT The relationships of wood density (WD) and compressive strength (CS) to longitudinal (VL), radial (VR), and tangential (VT) ultrasonic wave velocity within stems of 23-year-old Pinus massoniana trees planted in Vietnam were experimentally investigated. VL, VR, VT, WD, and CS were determined on a total of 100 small clear specimens (20 × 20 × 40 mm) cut from five sampled trees. Within the stem, radial position was highly significant for all traits, except for VR, whereas the variation in the vertical axis was significant only for WD but its contribution was small. VL had a positive linear relationship with both WD (r = 0.56) and CS (r = 0.80). There were statistically significant (0.1% level), but negative correlations of VR and VT with WD and CS. The best prediction of CS was obtained when both VL and WD were used together through calculation of dynamic Young's modulus (EL). The relationship between CS and EL was strong (r = 0.96). WD decreased axially and increased radially, patterns of variation that are consistent with other hard pine species.

Rapid and non-destructive detection of wood density based on NIR hyperspectral imaging technology and moisture correction methods.

Impact of moisture and NIR sensors on calibration transfer between predictive models of Eucalyptus grandis wood density

Pinus species currently planted for saw log production in the southern Cape, South Africa, present various challenges for growers and processors, including susceptibility to Fusarium circinatum, poor stem form, and various wood quality concerns. In this study P. patula × tecunumanii (low elevation) grown in the southern Cape were evaluated for its suitability as structural sawn timber material. The specific objectives of the study were to determine the flexural and other properties of interest such as the wood density, warp, and the grade recovery of the sawn boards. Sample trees were obtained from two 9-year old Camcore Pinus hybrid trials planted at Kruisfontein and Witelsbos estates. Before harvesting, the diameter at breast height, tree height and the stress wave time-of-flight, using a Fakopp Treesonic, were determined for each tree. The logs were processed into boards of dry dimension 38 × 114 × 3 000 mm. Wood density, bow and spring were measured before destructive testing in bending to determine the modulus of elasticity (MOE) and modulus of rupture (MOR) for each board. The results of this study showed that P. patula × tecunumanii (low elevation) grown in the southern Cape has excellent stiffness properties. Compared to previous research using comparable management regimes (specifically planting density), the only other species planted in South Africa that performed similarly in terms of the mean MOE of sawn boards were P. radiata and P. maximinoi from the southern Cape. The bending strength or MOR was not as good as the MOE, compared to SANS 10163-1 (2003) structural grade requirements, but should be adequate when efficient structural grading is performed. The sawn timber had relatively high and very uniform wood density while the bow and spring (warp) were relatively low. It can be concluded that P. patula × tecunumanii (low elevation) grown in the southern Cape has very good structural timber properties.

Drivers of biocapacity and global impact of the world's largest mangrove in ecological footprint accounting.

Abstract Deadwood is a crucial component of the global carbon budget, storing a substantial amount of carbon in forests. Understanding factors influencing deadwood turnover is therefore vital for predicting carbon cycling under climate change. While climate is an important driver, biotic factors, including wood and fungal traits, also play significant roles in deadwood decomposition. How parasitic fungi affect deadwood decomposition is likely important for global forest carbon turnover but is poorly understood. As opportunistic parasitic fungi, Armillaria species are capable of degrading wood components and altering wood traits. However, how (much) Armillaria drives deadwood decomposition remains unclear. To address this, we studied black pine ( Pinus nigra ), susceptible to Armillaria infection. We hypothesized that branches from infected stands would exhibit higher decay rates, even at given similar wood density. We collected naturally fallen Pinus nigra branches from infected and uninfected stands, sorted them by wood density and incubated them for 1 to 1.6 years under standardized conditions in a common garden experiment. Mass loss was measured and decomposition dynamic was modelled using a relative wood density approach. Our findings support the hypothesis that branches from infected Pinus nigra stands experience higher decay rates, backed up by molecular evidence. This difference may arise from Armillaria itself being a wood decay agent and from its effects via wood traits. These findings have broader implications for estimating deadwood stocks in forests impacted by climate‐induced fungal pathogens. Read the free Plain Language Summary for this article on the Journal blog.

This study is undertaken to provide a viable alternative to destructive test assessment which is prohibitively costly and makes it difficult to fully capture the bending strength distribution of timber. The bending strength of glued laminated Nigerian wood specie which from previous research have clearly not been sufficiently studied were carefully evaluated under controlled conditions. Five wood species—Afara ( Terminalia superba ), Akomu ( Pycnanthus angolensis ), Melina ( Gmelina arborea ), Iroko (Milicia excelsa), and Omo cedar ( Stereospermum accuminatissmum )—were tested for physical and mechanical properties at a mean moisture content level of 13%. Using standard procedures, density was determined for the wood species and found to be within low and medium densities. The glulam beams were produced using Phenol resorcinol formaldehyde, Urea formaldehyde, and Polyurethane adhesives. Furthermore, the bending strength of the beams was assessed parallel and perpendicular to the glue line using central point loading. Based on the strength assessment, four variables were evaluated as determinants for bending strength. These were wood density, wood species, adhesive type, and load direction. Analysis of variance was conducted to evaluate the significance of these variables as bending strength determinants in the beams. Furthermore, a stepwise regression method was used to develop the models, from which three models emerged with density, wood species, and load direction as predictors. Finally, these models were validated using an in-sample technique by splitting the data into a validation group and a training group in a ratio of 20% to 80%, respectively. The Pearson correlation between the predicted and experimental data was 0.847, 0.917, and 0.916 in the validation group and 0.824, 0.875, and 0.877 in the training group for models 1, 2, and 3, respectively. Higher correlation with the experimental data was found in the validation group than in the training group, thereby validating the models. These models are recommended for use because of the simplicity and efficiency of prediction.

Introduction The revelation of the assembly mechanism of plant communities in karst region has crucial implications for the restoration of degraded vegetation. Niche theory and neutral theory are the two main theories to elucidate community assembly of karst plant community. However, the relative significance of habitat filtration and biological action in community assembly remains a topic of debate. Methods By using measurement of plant functional traits, detection of phylogenetic signal (K value), and average shared variance, our investigation aimed to ascertain whether species coexistence in community assembly of primary forest is driven by habitat filtering or biotic constraints. Results In all 10 plant functional traits, leaf carbon (LC) had the lowest variation coefficient, whereas leaf area (LA) exhibited the highest. Significant phylogenetic signals ( P < 0.05) were identified for plant LC, LA, wood density (WD), leaf nitrogen (LN) and leaf phosphorus (LP). Phylogenetic signal strength (K < 1) of all traits indicated that the phylogenetic conservation of functional traits is relatively weak and may be influenced by environmental screening or convergent evolution. Both the phylogenetic net relatedness index (NRI) and nearest taxon index (NTI) were negative, indicating a divergent phylogenetic structure. Additionally, with the exception of LA and leaf length-width ratio (L/D), the mean pairwise trait distance indices (SES.PW) were greater than 0, suggesting a tendency towards aggregation in the functional trait structure. Furthermore, average shared variance demonstrated that variation in plant functional trait was predominantly influenced by soil fertility and topography of the sample Discussion Our finding indicated that the community assembly of primary forest plant was dominated by habitat filtering, which could significantly promote a more profound comprehension of natural restoration in karst degradation region.

Drought amplifies forest edge effects (EDE) by increasing microclimatic stress at edges (e.g., increasing temperature and reducing soil moisture), which heightens tree vulnerability to hydraulic failure. We assessed EDE's effects on hydraulic and functional traits of Qinghai spruce (Picea crassifolia Kom.) across environmental gradients in the Qilian Mountains. Edge trees experienced lower hydraulic conductivity (Ks) in both branches and roots during the drier year, suggesting that drought exacerbates EDE's negative effects on hydraulic efficiency. Percentage loss of hydraulic conductivity (PLC) did not differ between edge and interior trees, whereas water potential at 50% loss of hydraulic conductivity (P50) was less negative at the edge, indicating reduced hydraulic safety. The lack of correlation between Kmax and P50 suggests no trade-off between hydraulic efficiency and safety. Ks was correlated with wood density in branches but not in roots, presumably because soil buffers roots from environmental disturbance. At the edge, Ks in branches declined and PLC increased with increasing crown base height. Notably, EDE's impact on hydraulic function varied with slope types and local moisture conditions. Our results indicate that drought exacerbates trees' ecological vulnerability at edges and emphasize EDE's role in regulating the hydraulic response of trees to climate change.

Özet 1 : is an important natural material widely used in construction, furniture, paper, and energy due to its renewable, environmentally friendly, and aesthetic properties. Preferred in construction and industrial sectors due to its lightweight, high load-bearing capacity, and workability, wood contributes to environmental sustainability through its carbon storage capacity. Determining the technical properties of wood is crucial for assessing its suitability for its intended use. In this context, non-destructive testing methods are methods used to determine the physical and mechanical properties of wood samples without damaging the sample. Among these methods, the evaluation of samples taken with an increment borer provides information about the wood's density and anatomical structure. In this study, 15 logs of red pine (Pinus brutia) were taken with an increment borer from a stand in the Dalaman district of Mugla, located at an altitude of 15 m, and from a stand in the Aksu district of Isparta, located at an altitude of 1200 m. The air-dried densities of the resulting increments were determined, and their anatomical structures were examined microscopically. The effects of environmental conditions on wood quality were assessed by analyzing changes in wood density and structural properties of red pine individuals growing at different altitudes. This methodology revealed the effects of origin and habitat on wood using non-destructive methods.

The carbon present in the atmosphere is one of the main causes of global warming. However, vegetation is one of the most important carbon sinks and can be quantified through wood density. For this purpose, there are different invasive and non-invasive methodologies that use sophisticated, time-consuming and expensive equipment, but it is necessary to consider non-invasive, economical techniques that require less time. For this reason, this research aimed to i) compare the wood density obtained through the empirical method and water displacement and ii) demonstrate the validity of the empirical method as a methodology for measuring wood density for high Andean species. To perform the statistical analyses, it was necessary to group the species by growth habit (trees and shrubs), and all species were analyzed together. The comparison of means showed that wood densities did not show statistical differences (p value > 0.05), and linear regressions showed adjustments above 85% for tree, shrub and grouped species. This demonstrates the high similarity in wood density values. Previous research has found similar results to ours, and has also validated the empirical method in species from other latitudes. Based on the results of this study, it is suggested that the use of the empirical method is also suitable for measuring wood density in high Andean species. It is important to consider that this methodology reduces the work effort, time and even the use of equipment.

Combining wood traits as a promising timber origin verification and its application in the Brazilian trade chain.

Foliar nitrogen (N) and phosphorus (P) concentrations are of critical importance to plant productivity. Despite global declines in plant diversity, their effects on tree foliar N and P dynamics remain uncertain, especially under different mycorrhizal types and soil nutrient conditions. Based on a large biodiversity experiment in subtropical China, we assessed how neighborhood species richness and functional dissimilarity influence foliar N and P concentrations across 794 tree individuals, comprising three arbuscular mycorrhizal (AM) and five ectomycorrhizal (EcM) tree species, along natural soil total N gradients. At the neighborhood scale, foliar nutrients were jointly influenced by functional dissimilarity, mycorrhizal type, and soil N availability. Among dissimilarity metrics, wood density (WD) dissimilarity was the strongest predictor. Specifically, functional dissimilarity consistently increased foliar N and P concentrations in AM trees across the soil total N level, whereas its effects on EcM trees shifted from positive to negative with increasing soil total N content. These diversity-driven increases in foliar P concentration were further associated with enhanced tree growth. Our findings demonstrate that mycorrhizal type and soil N availability jointly mediate effects of neighborhood diversity on tree foliar nutrient status, with foliar P concentration playing a pivotal role in driving productivity responses to biodiversity in subtropical forests.

IntroductionUnderstanding the mechanisms of tree mortality in tropical ecosystems remains challenging, in part due to the high diversity of tree species and the inherently stochastic nature of mortality. Plant functional traits offer a mechanistic link between plant physiology and performance, yet their ability to predict growth and mortality remains poorly understood. Given recent increases in tree mortality rates in the Amazon forest following extreme drought and wind events, we tested if lower wood density and acquisitive plant functional traits were associated with increased growth and mortality for common co-occurring trees in the Central Amazon.MethodsSeventeen trees of different species with similar sizes but a range in wood density (WD) and wood traits were felled, then assessed for 27 different individual functional parameters, including whole tree architecture, stem xylem anatomical and hydraulic traits and leaf traits. Traits of the individual trees were related to stand-level growth and mortality rates collected periodically over 30 years from nearby permanent inventory plots.ResultsHigher wood density was associated with smaller leaf size, lower foliar base cations, lower stem water content and sapwood fraction, in agreement with the fast-slow plant economics spectrum. Lower wood density was associated with more acquisitive characteristics with greater hydraulic capacity and foliar nutrient concentrations, correlating with greater growth and mortality rates.DiscussionOur results show that lower wood density is part of a coordinated suite of traits linked to high resource acquisition, fast growth, and increased mortality risk, providing a functional framework for predicting species performance and forest vulnerability under future climate stress.

Xylem properties, such as wood density and conduit diameter, are linked to crown shape and size. Suppressed trees with smaller crowns tend to have denser wood and narrower conduits at the stem base, whereas dominant trees exhibit wider conduits and lower wood density. Given the tip-to-base widening of xylem conduits - an adaptation to counteract increasing hydraulic resistance with growth - we hypothesize that hydraulic path length (i.e., the distance from leaves to the stem base) is the primary driver of conduit size, independent of cambial age. To test this, we leveraged a phenomenon in managed forests: partial harvesting reduces stand density, triggering epicormic shoot formation along the stems of uncut (standing) trees. This downward shift in leaf distribution shortens the average hydraulic path length, allowing us to assess its influence on conduit formation in the standing trees. If conduit size is governed by hydraulic path length, newly formed tree rings should contain narrower conduits following epicormic shoot sprouting, despite the older cambial age. We analyzed wood samples from nine broadleaved trees across four species (Acer opalus obtusatum, Ostrya carpinifolia, Carpinus betulus, Sorbus aria), comparing the median conduit area in 3-4 annual rings before and after the harvesting of neighbouring trees. In trees with epicormic shoots, conduit size decreased by a factor ranging from 0.93 to 0.56 (p < 0.01). Conversely, the two trees without epicormic shoots exhibited no significant changes in conduit size. Our findings indicate that conduit size at the stem base is determined by hydraulic path length, rather than by cambial age. This suggests that newly formed leaves regulate the vascular conduits supplying them, leading to a hydraulic network structured by multiple, axially sectored pathways.

Acoustic non-destructive testing has become widely used in assessing the technical quality and internal condition of wood in wooden structures and growing trees. Meanwhile, the type of wood, its moisture content and grain direction, the presence of defects, as well as the frequency of ultrasonic transducers can have a significant impact on measuring the ultrasonic velocity in wood. The development of the instrumentation base, as well as the inconsistency of the results of previous studies, have served as the basis for conducting a separate series of experiments to study the effect of the frequency of ultrasonic transducers on the accuracy of indirect determination of the density, deformability and strength of wood under static bending. The research has been carried out on 176 samples of Scots pine (Pinus sylvestris L.) wood using ultrasonic devices Pulsar 2.2 (LLC SPE “Interpribor”, Chelyabinsk, Russia) and Pundit PL-200 (Proceq SA, Schwerzenbach, Switzerland) using ultrasonic transducers with nominal frequencies of 24, 54, 60 and 150 kHz. It has been confirmed that the frequency of ultrasonic transducers significantly affects the signal velocity and the dynamic modulus of elasticity, and that the density of wood is not related to the ultrasonic signal velocity. It has been established that the accuracy of predicting the modulus of elasticity and the ultimate strength of wood under static bending, estimated by the coefficient of determination (R2 = 0.88–0.91) of linear models of the relationship between these parameters and the dynamic modulus of elasticity, does not depend on the frequency of the ultrasonic transducer. At the same time, the quality of models for predicting the physico-chemical properties of wood by the ultrasound velocity is significantly lower compared to the dynamic modulus of elasticity parameter. The obtained regression models can be used for non-destructive evaluation of the mechanical properties of wood in growing pine trees and in the elements of wooden structures by the acoustic transmission method, and further research will be aimed at studying the variability of acoustic parameters of pine wood in growing trees.

Initial planting spacing affects stem diameter, tree height, and ultimately wood quality due to root and crown competition to reach light, water and nutrients. In the present study, we have investigated the effect of planting spacing and the longitudinal position along the stem height on wood density and mechanical properties of Populus deltoids. The study area has been located in the province of Mazandaran, in the north of Iran. 9 poplar trees (Populus deltoids Barter.ex Marsh) have been randomly selected in 3 PS of the Sari (Mazandaran) Wood and Paper Factory plantation 2×2, 2×3 and 3×3 m. 3 disc samples have been taken at 3 positions along longitudinal direction from bottom to upward (breast height, 50, and 75 % stem height) to measure wood density and investigate its mechanical properties according to ISO and ASTM standard. Testing samples have been prepared from mature wood. The results of the research have shown that the planting spacing significantly influences wood density and mechanical properties. The effect of longitudinal position on the modulus of elasticity has been significant with no changes in the wood density, modulus of rupture, compression parallel to grain and nail withdrawal resistance values. The most optimal initial spacing in view of wood density and mechanical properties has been found at the planting spacing 2×2 m. Analysis of wood quality characteristics indicates that closer PS is more suitable for poplar plantation.

ABSTRACT The IML PD series Resi instrument is widely used for wood quality assessment, valued for its speed, cost-effectiveness, and precision. Currently, it is not known to what degree needle diameters are an issue for quantifying wood density and stiffness. Additionally, some anecdotal evidence suggests that the battery might have an effect as well. To quantify the impact of needle diameter, twelve new Resi needles (3.08–3.30 mm) were tested using a single IML Resi PD 500 instrument on a southern pine (Pinus elliottii var. elliottii (Engelm) × Pinus caribaea var. hondurensis (Sénéclauze)) log with settings of 200 cm/min feed speed and 3500 rpm. Each needle was tested 44 times, along with five different batteries. The maximum difference in drilling resistance between needles was 2.3%, corresponding to a 15.4 kg/m³ difference in predicted basic density. This occurred with extreme needle diameters (3.08 mm or 3.21–3.30 mm), while needles within the typical 3.11–3.20 mm range showed no significant difference. Feed resistance was highly sensitive to needle diameter changes, with an 11.5% difference translating to a 108.1 kg/m³ density difference. Battery effects were minimal, causing only a 0.5% amplitude difference in drilling resistance.

Among the many interesting topics in the field of Wood Science and Technology is a fascinating story about research and development on drying wood products with high-frequency electric current. Historically, it can be traced back over decades.Heat transfer to and evaporation of moisture from wood may be accomplished with high frequency current depending on its dielectric properties. Because wood is generally heterogeneous, these properties vary not only with the frequency of the current and the field orientation, but also with the moisture content, temperature, and density of wood. Considering these parameters and the specific heat of the material, estimates of power absorption can be made.In an attempt to develop this technology, research covered many products from paper and veneer to lumber and heavy timbers. Much emphasis, however, has been placed on wood species and/or products with larger dimensions that are difficult or impossible to dry when using conventional drying methods. The advantages of employing dielectric heating were found to be rapid and fairly uniform heat transfer often to solidly stacked timbers, very high drying rates, and avoidance of various drying defects including any significant case-hardening and oxidative discoloration of the wood.During the last two decades, the development focused mainly on drying lumber in vacuum kilns using dielectric heating, often termed high-frequency/vacuum drying. It has been justified economically on the basis of increased throughput and higher quality. Existing industrial installations provide a positive picture for higher value products. The economics should improve with advances in available equipment, better basic understanding and more practical experience with industrial units now operating. Also, the combination of high-frequency/vacuum drying with other systems, such as moisture leveling after primary drying or pre-heating prior to the high-frequency/vacuum step, hold promise for further technical improvement.

ABSTRACTAimRepeated droughts have proven more harmful to forest growth than single extreme droughts. However, the impacts of drought durations on global forests and their underlying drivers remain poorly understood. The drought responses can be evaluated by drought sensitivity (resistance, Rt) and the post‐drought recovery rate (resilience, Rs). Differing drought responses are attributed to the different evolutionary strategies of species, which are shaped by their distinct physiological traits. Given the spatial variability in climate warming rates and aridification, understanding how trees respond to droughts of different characteristics (duration, recurrence, severity) in forested biomes is crucial to forecast productivity trends.LocationGlobal.Time Period1950–2020.Major Taxa StudiedTree species.MethodsBy explicitly considering different drought durations (single‐year and multi‐year extreme droughts), we assessed drought impacts on the growth of global forests. In addition, the roles played by environmental conditions (climate, soils), stand attributes (age, density), functional traits (wood density, leaf and hydraulic traits), and phylogeny in forest responses to drought were also considered. We used three tree‐ring databases (global ITRDB, European GenTree, and tropical data) accounting for 4374 site chronologies during the period 1950–2020, and quantified patterns in tree responses to drought in different climatic regions and biomes, including tropical forests.ResultsIn general, significantly higher Rt and Rs were observed in humid regions. Interestingly, while multi‐year extreme droughts caused worse impacts than single extreme droughts on Rs, they did not affect Rt among drought events. Specifically, Rt in arid regions was phylogenetically conserved and largely depended on wood density (WD) and hydraulic safety margin (HSM), while in humid regions, it was closely linked to climate, SLA, and HSM.Main ConclusionsThese findings provide new insights on the forest responses to different types of droughts, emphasising an ecological and evolutionary framework of jointly considering environmental conditions, phylogeny, and functional traits in predicting growth resilience to guide management under more arid conditions.